Avalanche Forecast

Issued: Dec 27th, 2012 9:44AM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs and Loose Dry.

mbender, Avalanche Canada

Purcells.

Summary

Confidence

Fair - Wind speed or direction are uncertain on Saturday

Weather Forecast

Friday:Â Isolated flurries with overcast skies,Â winds light from the west. Alpine temperatures near -10.Saturday:Â Light precipitation, winds will be light west and northwest. Alpine temperatures will be near -10.Sunday: A weak ridge of high pressure should bring drier conditions with upper level temperatures remaining cool.

Avalanche Summary

There was recent (Dec 26) report of a size 3 skier triggered avalanche in the Dogtooth range. Triggered from a thin area on a cross-loaded west facing feature at the upper end of the tree-line elevation, it then stepped down to the early November crust. There are no other observations to report at this time.

Snowpack Summary

A wind event from last week formed relatively deep wind slabs in the alpine. New snow combined with wind has formed fresh wind slabs on the surface and/or buried newly formed surface hoar in sheltered, open areas at and below tree line. The mid-pack is reported to be settling well. Recent reports indicate the late November surface hoar (near the middle of the snowpack) and early November crust (near the base of the snowpack) have been mostly inactive as of late. It's important to note that professionals are still cautious about these lingering persistent slab problems, but the likelihood of triggering is low. Be wary of steep complex terrain with a shallow snowpack, where triggering a persistent weakness is more likely.

Problems

Wind Slabs

Watch for newly formed and buried windslabs in the lee of and in cross loaded terrain features. lee, cross loaded

Be cautious as you transition into wind affected terrain.>Use ridges or ribs to avoid pockets of wind loaded snow.>Avoid thin, rocky or sparsely-treed slopes.>Stay well to the windward side of corniced ridges.>

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 5

Loose Dry

Expect the unconsolidated surface snow to sluff in steep terrain.

Be cautious of sluffing in steep terrain.>On steep slopes, pull over periodically or cut into a new line to manage sluffing.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Dec 28th, 2012 2:00PM